I was on Enchantment in January of this year, escorting a large group that included teenagers. Everyone had a great time. The older teens found lots of other kids their own age, and tended to hang out together on deck. The younger teens had fun in the kids' program, which is divided up into age groups with appropriate activities.
I found that there was always something for everyone to do when they wanted to, and space to just veg out when they wanted to do that.
Let us know how it went when you get back.